Feeds on a variety of animals--bivalves, limpets, snails, brachiopods, barnacles, and tunicates. Can evert its stomach (up to a distance equal to half the length of a ray). Several limpets exhibit escape responses from this species. May have a symbiotic scaleworm (Arctonoe fragilis
) living in the ambulacral groove or on the body surface (photo). In Alaska one can often find the young of the Alaska King Crab (Paralithodes camtschaticus
) nestled between the rays of this seastar. Predators include gulls (especially in Alaska where they are common intertidally), Solaster dawsoni
,and Pycnopodia helianthoides
; and attacks by the rose star Crossaster papposus
and by Alaska King Crab Paralithodes camtschaticus
have been observed. Tolerant of reduced salinities down to 20 ppt.